Radial Mixing in the Early Solar System: Meteoritic and Cometary Evidence Planet Formation and Evolution: The Solar System and Extrasolar Planets Tübingen M. Trieloff University of Heidelberg, Institute of Geosciences, Heidelberg, Germany

Radial Mixing in the Early Solar System: Meteoritic and Cometary Evidence Astrophysical evidence: Observations of protoplanetary discs (extrasolar) Cometary evidence (early solar system): Hale Bopp (IR observations) Wild-2 dust returned by STARDUST (laboratory analyses) Meteoritic evidence (early solar system asteroids): Flash heated objects in chondrites: Chondrules and calcium,aluminum rich inclusions (CAIs)

IR spectroscopy of protoplanetary disks: Mg silicates olivine+pyroxene – crystalline fraction higher in inner disks (van Boekel et al. 2004) % % % % % %

comets Crystalline fractions in some outer disks considerable, similar to solar system comets (Wooden et al., 2000)  Dust processing in disks and radial mixing into outer disks IR spectroscopy of protoplanetary disks: Mg silicates olivine+pyroxene – crystalline fraction higher in inner disks (van Boekel et al. 2004) % % % %

Refractory forsterite grain from STARDUST collector Silicates (Olv, Px, Fs), glass, Fe-Ni sulfide, refractory minerals (An,Di,Sp), CAI: Inti No phyllosilicates and carbonates in Wild- 2 particles CAI „Inti“ Cometary grains from comet Wild-2 returned by the STARDUST mission

Astrophysical evidence: Observations of protoplanetary discs (extrasolar) Cometary evidence (early solar system): Hale Bopp (IR observations) Wild-2 dust returned by STARDUST (laboratory analyses) Meteoritic evidence (early solar system asteroids): Flash heated objects in chondrites: Chondrules and calcium,aluminum rich inclusions (CAIs) Radial Mixing in the Early Solar System: Meteoritic and Cometary Evidence Indicator: High temperature processing (crystallinity, refractory rich)

Meteorites: Fragments of small bodies in the solar system, the asteroids between Mars and Jupiter Inferred number of parent bodies is >100 (accretion to full-sized planet inhibited by early Jupiter?!) Innisfree

Carbonaceous chondrites (CI, CM, CV, CO, …): (mild thermal/aqueous metamorphism) Ca,Al-rich inclusions Chondrules Allende Fine grained matrix (volatile rich)  undifferentiated, e.g. preaccretional structures preserved  undifferentiated, e.g. ‘cosmic’ Fe,Ni abundance <900 K  K  K

Metal abundance of chondrites: Origin from primitive, undifferentiated parent bodies Variation of oxidation state and metal abundance: Origin from compositionally different parent asteroids Ordinary chondrites: H: high Fe L: Low Fe LL: Low total, low metallic Fe Enstatite chondrites Carbonaceous chondrites: named after main member CI (Ivuna) CM (Mighei) CV (Vigarano) CO (Ornans)

Astrophysical evidence: Observations of protoplanetary discs (extrasolar) Cometary evidence (early solar system): Hale Bopp (IR observations) Wild-2 dust returned by STARDUST (laboratory analyses) Meteoritic evidence (early solar system asteroids): Flash heated objects in chondrites: Chondrules and calcium,aluminum rich inclusions (CAIs) Radial Mixing in the Early Solar System: Meteoritic and Cometary Evidence Indicator: High temperature processing (crystallinity, refractory rich) High temperature processing of chondrules and CAIs: indicative of radial mixing?

Nuth (2001) … some models assume the answer is YES

… what about (abundant) chondrules? … fast cooling ( K / hour; e.g. former melt glass) … local flash heating (shock, lightning, planetary collisions) in the asteroid belt region? … do chronology and chemical complementarity allow large scale movements?

CV3 Efremovka matrix chondrules enstatite (intermediate Mg) forsterite (high Mg) solar Mg/Si-ratio solar Mg-, Si-composition Chemical complementarity of chondrules and matrix in CV chondrites: Exemplified by Mg and Si (J. Wood, P. Bland, H. Palme)

Chemical complementarity of chondrules and matrix in CR chondrites: Exemplified by Mg and Si (J. Wood, P. Bland, H. Palme)

Matrix and chondrules of specific chondrites formed from Mg/Si= solar precursor material, and were not separated (e.g. by radial drift) before chondrite accretion  growth timescales short when compared to radial drift timescales [% chondrules] CV chondrules CV matrix CR matrix CR chondrules

What about isotope chronology of chondrule formation? Ca,Al-rich inclusions Chondrules ± 0.6 Ma (U-Pb-Pb, CV Efremovka; Amelin et al., 2002) Allende ± 0.6 Ma ( CR Acfer059; Amelin et al., 2002) 2-3 Ma age difference supported by 26 Al- 26 Mg chronometry

Short-lived nuclides in the early solar system and their half-lives: 26 Al  26 Mg (0.72 Ma) 129 I  129 Xe (16 Ma) 182 Hf  182 W (9 Ma) 53 Mn  53 Cr (3.7 Ma) 244 Pu  fission (80 Ma) 10 Be  10 B (1.5 Ma) 41 Ca  41 K (0.1 Ma) 60 Fe  60 Ni (1.5 Ma) … nucleosynthesis in mass-rich stars … or nuclear reactions due to solar irradiation ( 10 Be) Trapezium (Orion nebula)... injected into protoplanetary disks (solar mass)  Radiometric dating  Planetesimal heating

26 Al as tool for radiometric dating: 26 Al- 26 Mg ages of individual chondrules of different chondritic parent bodies (Kita, Nagahara, Russell, Mostefaoui etc.)

26 Al as planetesimal heat source: Extent of heating as a function of 26 Al content and accretion time after CAIs

Mean 26 Al- 26 Mg ages of chondrules of different chondritic parent bodies correlate with heating degree of parent bodies: stronger heated planetesimals have earlier formed chondrule populations

Astrophysical evidence: Observations of protoplanetary discs (extrasolar) Cometary evidence (early solar system): Hale Bopp (IR observations) Wild-2 dust returned by STARDUST (laboratory analyses) Meteoritic evidence (early solar system asteroids): Flash heated objects in chondrites: Chondrules and calcium,aluminum rich inclusions (CAIs) Radial Mixing in the Early Solar System: Meteoritic and Cometary Evidence Indicator: High temperature processing (crystallinity, refractory rich) High temperature processing of chondrules: indicative of radial mixing? High temperature processing of CAIs: indicative of radial mixing? NO (only possible if fast movement with micron dust)

Fassait (Ti-rich diopside) Anorthite Zoned type B1 CAI from Leoville (CV) Melilite

from: Davis & Richter 2005 Fe-Ni-metal Enstatite – MgSiO 3 Forsterite – Mg 2 SiO 4 Gehlenite Ca 2 Al 2 SiO 7 Hibonite CaAl 12 O 19 Anorthite Fraction CI chondritic composition condensed Cpx Albite Spl Condensation sequence of minerals in a cooling solar nebula: Ca,Al minerals important high temperature condensates

CAIs and refractory inclusions:  Rare (0.1% - 13%)  Carrier of 16 O enrichment in carbonaceous chondrites  Slower cooling than chondrules (10 K / hour)  Resided 2-4 Ma in solar nebula  Independent chemical component

Astrophysical evidence: Observations of protoplanetary discs (extrasolar) Cometary evidence (early solar system): Hale Bopp (IR observations) Wild-2 dust returned by STARDUST (laboratory analyses) Meteoritic evidence (early solar system asteroids): Flash heated objects in chondrites: Chondrules and calcium,aluminum rich inclusions (CAIs) Radial Mixing in the Early Solar System: Meteoritic and Cometary Evidence Indicator: High temperature processing (crystallinity, refractory rich) High temperature processing of chondrules: indicative of radial mixing? High temperature processing of CAIs: indicative of radial mixing? NO (only possible if fast movement with micron dust) Good candidates

Conclusions: High degree of crystallinity or high temperature processing is not a compelling proof of radial mixing High temperature processing of CAIs suggests radial outward transport in solar nebula, but reasoning requires broad body of evidence Future modeling needs to evaluate different mechanisms (meridional flows, etc.) and must check for element fractionations Radial Mixing in the Early Solar System: Meteoritic and Cometary Evidence Indicator: High temperature processing (crystallinity, refractory rich) High temperature processing of chondrules: indicative of radial mixing? High temperature processing of CAIs: indicative of radial mixing? NO (only possible if fast movement with micron dust) Good candidates